Prosthesis for the repair of soft tissue defects

ABSTRACT

A prothesis for the repair of soft tissue defects is provided. The prosthesis is made of a first portion comprising a first material which substantially does not incorporate into the host tissue and a second portion comprised of a second material which substantially incorporates into the host tissue, or which increases the structural integrity of the prosthesis, or which does both. A process for repairing a soft tissue defect by surgically implanting the prosthesis is also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit under 35 U. S. C. §120 is acontinuation-in part of U.S. application Ser. No. 08/024,233 filed Mar.1, 1993, a continuation of application Ser. No. 08/002,394, filed Jan.13, 1993, now abandoned.

FIELD OF THE INVENTION

This invention relates to a prosthesis for the repair of soft tissuedefects, and to methods for repairing such defects.

BACKGROUND OF THE INVENTION

Soft tissue defects are defects in the soft tissue of an animal or humanpatient which lead to the formation of an opening in the tissue. Theycan occur, for example, in a hernia or as the result of extirpativetumor surgery. Such defects can be repaired by closing the openingformed from the defect by suturing, or by "patching" the opening with aprosthesis.

One of the most common soft tissue defects is an abdominal hernia. Ahernia is an abnormal opening in the abdominal wall. A normal abdominalwall consists of layers of skin, fat, fascia, muscle and peritoneum.Hernias occur when there is a defect in the wall, and become significantwhen abdominal viscera (i.e., intestines or other internal organs)protrude through the defect, causing pain and presenting the danger ofstrangulation. A conventional procedure to repair a hernia utilizessutures to close the opening and restore the integrity of the abdominalwall. Often, however, the fascial tissues involved have been weakened tothe point that they will not maintain a repair if simply suturedtogether.

The repair of a large incisional hernia, particularly one which occursin tissues weakened by previous surgery or in tissues of obese patients,remains a formidable task in general surgery. Factors such as obesity,chronic pulmonary disease, prior surgery, wound infection and seroma orhematoma formation continue to exert adverse influences on wound healingand increase the chance of recurrent herniation. Often, the abdominalwall tissues of these patients are severely compromised and weakenedsuch that they will not support a primary repair, and any such closuremay be associated with a significant recurrence rate.

Studies on the natural history of incisional hernias demonstrate anincidence of from 0.5% to 13.9% occurring following abdominal surgery.See, for example, Mc Vay et al., Hernia, Charles C. Thomas, ed., pp.33-38, 1954; Blaustedt et al., Acta Chir. Scand., 138: 275 (1972). Inaddition, long term studies have demonstrated a significant chance ofthe appearance of an incisional hernia long after the original surgery.See, for example, Mudge et al., Br. J. Surg., 72: 70-71 (1985). The highfailure rate following standard surgical suture repairs of incisionalhernias has been discussed by many authors with recurrence rates as highas between 40% to 50%. See, for example, Langer et al., Acta Chir.Scand., 151: 217-219 (1985); George et al., Ann. R. Coll. Surg., 68(4):185-187 (1986).

To reduce the chance of hernia recurrence and to allow for moresatisfactory closure of the abdominal wall, the insertion of aprosthetic material may be required to accomplish the hernia repair.Several prosthetic materials have been proposed and are available foruse as a substitute for the patient's tissue. These materials havedifferent biological properties and have various advantages anddisadvantages associated with them.

Both absorbable and nonabsorbable synthetic materials are availablecommercially for use in hernia repairs. Absorbable meshes (polyglycolicacid or polyglactin) disintegrate, and thus will not maintain a herniarepair. Nonabsorbable materials, however, are useful, and includetantalum mesh, stainless steel mesh, polyester cloth, polyestersheeting, polymeric meshes (e.g., MARLEX® and SURGI-PRO®) aspolypropylene mesh, dacron mesh and nylon mesh, polyvinyl sponge,acrylic cloth, and expanded polytetrafluoroethylene (PTFE) (e.g.,GORE-TEX®).

Two of the more readily available products are expanded PTFE andpolypropylene mesh. These materials have been used independently inhernia repair. See, for example, Bauer et al., Am. Surg., 206: 765-769(1987); Usher et al., Arch. Surg., 78: 138-145 (1959). They havedifferent properties with regard to their degree of "incorporation,"i.e., their fixation, into the host tissue.

Expanded PTFE is described in U.S. Pat. No. 4,187,390, and it isavailable from W. L. Gore & Associates, Inc. under the trade nameGORE-TEX®. It can be obtained as a sheet of material which may besutured in place over the soft tissue defect. Expanded PTFEsubstantially does not "incorporate" into the host tissues. That is, thetissues of a patient, over time, may incorporate somewhat into expandedPTFE, but this response is different from, and has a lesser degree offixation than, that response which is observed with other materials,such as polypropylene mesh. This feature is a disadvantage whenlong-term fixation is desired, but represents a distinct advantage whenexposed viscera such as intestines or other internal organs will comeinto contact with the material used in the soft tissue repair. That is,while other repair materials have been reported to cause major injury toabdominal viscera because the viscera incorporate into the repairmaterial, the lesser degree of incorporation of expanded PTFE preventssuch injuries. While there have been some reports that PTFE can adhereto viscera, there have been no reports of significant injury to visceraas a result of such incorporation.

Because it is a soft material, expanded PTFE may, when sutured in place,bulge somewhat and thereby provide a less than desirable cosmeticeffect. Additionally, its poor ability to incorporate into the host'stissue may result in retraction or wrinkling and curling of the materialif its lateral fixation, i.e., fixation by sutures, breaks loose or isdisrupted.

The other commonly-used repair material, polypropylene mesh, isdescribed in U.S. Pat. No. 4,769,038, and is available from C. R. Bard,Inc. under the trade name MARLEX®. The polypropylene mesh substantiallyincorporates itself into the patient's tissue, thereby fixing itselfsecurely in place. Although this provides excellent long-term placementin the fascia and may protect against recurrent herniation over time,the substantial tissue incorporation may result in severe injury to anyviscera which inadvertently may come in close contact with it for aprolonged period of time. Scattered reports of viscera injury exist andmany surgeons have anecdotal evidence of the potential harm created insuch situations. See, for example, Schneider et. al., Am. Surg. 45:337-339 (1979). In one instance, a patient developed a small bowelfistula through polypropylene mesh one year following an otherwiseunremarkable ventral hernia repair.

Thus, the currently available prosthesis, while providing some neededproperties, present certain inherent disadvantages. That is, there is noprosthesis available which will both (i) lessen the likelihood ofviscera injury by providing a surface which substantially does notincorporate into the host tissue and (ii) improve the incorporation ofthe prosthesis into the host by providing a surface which substantiallyincorporates into host tissue and/or which increases the structuralintegrity of the prosthesis by providing a component which increases thestructural integrity. Thus, there is a continuing need for a prosthesiswhich will accomplish the foregoing objectives.

SUMMARY OF THE INVENTION

Accordingly, it is the object of the present invention to provide aprosthesis for repairing a soft tissue defect.

It is a further object of the present invention to provide a process forrepairing a soft tissue defect.

Thus, a prothesis for the repair of soft tissue defects is provided. Theprosthesis comprises a first portion comprised of a first material whichsubstantially does not incorporate into the host tissue and a secondportion comprised of a second material which substantially incorporatesinto the host tissue or which increases the structural integrity of theprosthesis, or which does both.

In one embodiment, the first and second portions are arranged to formlayers, whereas in another embodiment, the first and second portionsform a single layer.

In other embodiments, the first and second portions are substantiallynot joined together. In yet other embodiments, the first and secondportions are at least partially joined together, e.g., by sutures,hemoclips and/or bonding.

In other embodiments, the first and second portions are of the same ordifferent areas.

Yet other advantageous embodiments of the prosthesis are described.

Also provided is a process for repairing a soft tissue defect of apatient by surgically implanting any prosthesis of this inventionadjacent the soft tissue defect. In one embodiment of the process, thefirst and second portions are both surgically attached to the fascia,whereas in another embodiment, the second portion is surgically attachedto the fascia while the first portion is surgically attached to theperitoneum.

Additional objects and advantages of the present invention will be setforth in part in the description that follows, and in part will beobvious from the description, or may be learned by practice of theinvention. The objects and advantages may be realized and obtained bymeans of the processes and compositions particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view in cross-section of an embodiment of a prosthesisin accordance with this invention;

FIG. 2 is a side view in cross-section of another embodiment of aprosthesis in accordance with this invention;

FIG. 3 is a top view of another embodiment of a prosthesis in accordancewith this invention, in which the dotted lines represent the boundariesof a first portion which is located below the second portion;

FIG. 4 is a top view of another embodiment of a prosthesis in accordancewith this invention, in which the dotted lines represent the boundariesof the first portion which is located below the second portion;

FIG. 5 is a view in cross-section of another embodiment of a prosthesisin accordance with this invention;

FIG. 6 is a view in cross-section of another embodiment of a prosthesisin accordance with this invention; FIG. 7 is a top view of yet anotherembodiment of a prosthesis in accordance with this invention; FIG. 8 isa side view in cross-section of the prosthesis illustrated in FIG. 7;

FIG. 9 is a view in cross-section of another embodiment of a prosthesisin accordance with this invention;

FIG. 10 is a view in cross-section of the normal anatomy of theabdominal wall;

FIG. 11 is a view in cross-section of an abdominal wall hernia;

FIG. 12 is a view in cross-section of an abdominal wall that has beenrepaired using a prosthesis of this invention, wherein the first andsecond portions are arranged in layers and are sutured to the fascia;

FIG. 13 is a view in cross-section of an abdominal wall that has beenrepaired using a prosthesis of this invention, wherein the first andsecond portions are arranged in layers and wherein the second portion issutured to the fascia and the first portion is sutured to theperitoneum;

FIG. 14 is a view in cross-section of an abdominal wall that has beenrepaired using a prosthesis of this invention, wherein the secondportion is larger in area than the first portion, and wherein the secondportion is separately sutured to the underlying fascia away from thehernia defect;

FIG. 15 is an illustration of an abdominal wall repair (skin andsubcutaneous fat layers not shown) using a prosthesis of this invention,wherein in the figure the dotted lines represent the boundaries of afirst portion that is located below a second portion, and a hernia whichis located below the first portion; and

FIG. 16 is a view in cross-section of the abdominal wall repairillustrated in FIG. 15;

FIG. 17 is a view in cross-section of an abdominal wall that has beenrepaired using a prosthesis of this invention, wherein the first portionis sized to extend beyond the defect, and wherein the first portion issutured through the peritoneum to the fascia, and the second portion issutured to the fascia;

FIGS. 18 is a top view of the abdominal wall repair illustrated in FIG.17, wherein the dotted line represents the first portion.

FIG. 19 is a top view of the abdominal wall repair illustrated in FIG.17, wherein the dotted line represents the first portion and the shadedarea represents the second portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The prosthesis of the present invention is suitable for use in therepair of soft tissue defects, such as soft tissue defects resultingfrom incisional hernias and soft tissue defects resulting fromextirpative tumor surgery. It is also suitable for use in cancersurgeries, for example, in surgeries involving sarcoma of theextremities where saving a limb is a goal. Other applications of theprosthesis of the present invention include laparoscopic inguinal herniarepair, standard inguinal hernia repair, umbilical hernia repair,paracolostomy hernia repair, femora hernia repair, lumbar hernia repair,and the repair of other abdominal wall defects, thoracic wall defectsand diaphragmatic hernias and defects.

The prosthesis of the present invention comprises a first portioncomprising a first material which substantially does not incorporateinto the host tissue, and a second portion comprising a second materialwhich substantially incorporates into the host tissue, or whichincreases the structural integrity of the prosthesis, or which doesboth.

By the phrase "substantially does not incorporate into the host tissue,"it is meant that the first portion will exhibit the type ofincorporation generally observed with repairs using expanded PTFE. Thatis, while there is some tissue growth onto the prosthesis over time,such growth is of the type which generally does not result in damage toviscera. Typically, such growth may be characterized by formation of a"capsule" or band, which is adhered to the surface of the PTFE, butwhich is not substantially irreversibly fixed to it. A capsule is asmooth, uniform type of scar tissue which is generally easy to break upand/or remove from the expanded PTFE surface.

The observation that expanded PTFE substantially does not incorporate isconsistent with the structure of expanded PTFE, which is an imporousmaterial when viewed with the naked eye. There are no visible aperturesfor the tissue to grow through and form a substantial incorporation.While not wishing to be bound by any theory, it is believed that theexpanded PTFE substantially does not incorporate into host tissuebecause its surface does not facilitate as substantial a fibroblasticreaction in the host tissue. Thus, one acceptable first material isexpanded PTFE. This is available from W.L. Gore & Associates under thename GORE-TEX® (see U.S. Pat. No. 4,187,390). While some incorporationinto host tissue may be observed with this material, no reports ofsignificant injury to viscera as a result of this attachment have beenreported. Thus, for the purpose of this invention, expanded PTFEsubstantially does not incorporate into host tissue. Those skilled inthe art may recognize other suitable first materials.

The second material is one which substantially incorporates into thehost tissue, or which increases the structural integrity of theprosthesis, or which does both. By "substantially incorporates into thehost tissue," it is meant that, over time, the host tissue will growsubstantially onto or substantially attach itself to the secondmaterial. Substantial incorporation is the type that is generallyobserved with repairs using polypropylene mesh. That is, with time thepatient's fibrous and collagenous tissue substantially completelyovergrow the mesh, growing through the openings therein and firmlyaffixing the mesh to the tissue. Eventually, it becomes difficult torecognize where the patient's tissue stops and the mesh begins. Suchincorporation is consistent with the structure of the mesh, which has anarray of apertures visible to the naked eye, through which the tissuecan grow to achieve substantial fixation. Again, not wishing to be boundby any theory, it is believed that the polypropylene mesh, in contrastto the expanded PTFE, substantially incorporates into the host tissuebecause it facilitates a substantial fibroblastic reaction in the hosttissue.

The skilled artisan who is familiar with surgical repair of tissuedefects using a prosthesis readily will appreciate the meaning of thephrases "substantially does not incorporate" and "substantiallyincorporates" and their relative differences in type and degree offixation to the patient's tissues.

Alternatively, the second material can increase the structural integrityof the prosthesis by reducing the effects of bulging, wrinkling andcurling which may be associated with the first material. Suitable secondmaterials may both substantially incorporate into the host tissue andincrease the structural integrity of the prosthesis. Examples ofsuitable second materials include polypropylene mesh, prolene mesh, ormersilene mesh.

As mentioned, one acceptable second material is a polypropylene mesh,which is available from C. R. Bard, Inc. under the trade name MARLEX®(see U.S. Pat. No. 4,769,038). MARLEX® is one of the most commonly usedmaterials in the repair of hernias because it incorporates rapidly intothe host tissue and provides structural integrity to the prosthesis suchthat bulging, wrinkling and curling are not observed.

The two portions may be arranged to form more than one layer orsubstantially one layer, or the portions may be integrally formed. Forexample, the portions may be arranged in two layers, wherein one portionis on top of the other portion. Alternatively, the portions may bearranged in substantially one layer, wherein the portions are adjacenteach other, for example, wherein the second portion substantiallysurrounds the first portion. In this way, a prosthesis could be madesuch that the first portion substantially covers any opening created bythe soft tissue defect, and the second portion facilitates surgicalattachment to, and incorporation into, the host tissue. Alsocontemplated is an arrangement wherein the two portions are integrallyformed.

Alternatively, multiple layers of each material is also possible, eithertogether or separated by one or more layers of another material, e.g.,two first portions with a second portion therebetween. Optionally,additional layers which provide advantageous properties may be added.For example, an additional layer which enhances the overall resistanceto bulging and/or which substantially incorporates into the host tissuemay be added. Also, a layer comprising a material or composition(including, e.g., a gel) which completely absorbs into the host tissueor dissolves may be added. The skilled artisan will realize yet othercombinations and permutations in which the first and second portions,either alone or with other layers, can be arranged to accomplish theobjectives of this invention.

The two portions independently may be of any shape or size suited to fitthe particular soft tissue defect. Examples of suitable shapes includecircles, ovals, rectangles, squares and irregular shapes. The twoportions may be of essentially the same dimensions or of differentdimensions, such that one portion is larger than the other portion.

The portions may be separate, i.e., not joined together. Alternatively,they may be partially or substantially entirely joined together. Joiningcan be achieved by mechanical methods, such as by suturing or by the useof metal clips, for example, hemoclips, or by other methods, such aschemical or thermal bonding.

One advantageous embodiment provides a first portion of expanded PTFE(e.g., GORE-TEX®) which substantially entirely covers the soft tissuedefect and a second portion of polypropylene mesh (e.g., MARLEX®) whichfacilitates incorporation into the host tissue. Such design combines thebenefits associated with the mesh and the expanded PTFE while minimizingthe drawbacks encountered when each is used separately. The expandedPTFE portion protects any underlying tissue, for example, viscera, whichmay come in contact with the prosthesis from being incorporated into theprosthesis. This prevents the severe injuries which may occur ifinternal organs, for example, small intestines, are inadvertentlyexposed to and subsequently incorporate into the polymeric mesh portion.The polymeric mesh portion provides additional structural integrity tothe prosthesis, preventing the undesirable effects of bulging associatedwith prostheses which are comprised primarily of expanded PTFE. Thepolymeric mesh portion also substantially incorporates into thepatient's tissue. This incorporation occurs rapidly, and providessecure, long-term fixation of the prosthesis into the host tissue.Moreover, when the two portions are joined together, the strength of thepolymeric mesh portion will minimize the wrinkling and curling that mayoccur over time with the expanded PTFE portion.

The prosthesis of this invention is implanted into the patient usingstandard surgical techniques such that substantially all of the defectin the patient's soft tissue is closed. This can be accomplished, forexample, by fastening the prosthesis using one or more layers ofsuturing. For example, when performing abdominal repairs, both the firstand second portions may be attached to the same layer of the abdominalwall, e.g., the fascia. Alternatively, the first portion may be attachedto the peritoneum. Advantageously, however, at least one of the portionsis attached to the fascia because it is a stronger layer and thusprovides a stronger repair. On the other hand, the peritoneum is weakerand thus a weaker repair would be effected were both the first andsecond portions attached thereto. Those skilled in the art willrecognize other methods of attaching a prosthesis of this invention.

When repairing an incisional hernia, the prosthesis is anchored intoplace according to standard surgical procedures. It is sutured to amargin of healthy fascial tissue, and the size of the prosthesis isdetermined by the size of the defect. Advantageously, the patient isgiven antibiotics perioperatively, and a drain is left in place in thesubcutaneous tissue for about 48 hours. The drain is then removed usingstandard surgical procedures. Further, the patient advantageously wearsan abdominal binder, i.e., an elastic girdle, for 7-10 days followingsurgery.

The prosthesis of this invention has a further benefit in that it canminimize complications that can accompany soft tissue repairs.Specifically, the use of the prosthesis of this invention in atension-free closure may be associated with less pain and less incidenceof postoperative fluid accumulation (seroma). There also may be benefitin the increased tensile strength of the repair.

The invention will be described in further detail with reference to theaccompanying Figures. It is to be understood that these Figures are forillustration only, and do not limit of the scope of the invention.

FIG. 1 is a view in cross-section of one embodiment of a prosthesis inaccordance with this invention. The first and second portions, 10 and12, respectively, are of essentially the same dimensions, and are of anyshape or size suitable to the soft tissue defect, as discussed above.The first and second portions are arranged in substantially two layers,and are substantially entirely joined together along the interface 14.The joining may be accomplished by any known method, as discussed above.Advantageously, the portions may be joined using hemoclips (not shown).

FIG. 2 illustrates a view in cross-section of another embodiment of aprosthesis in accordance with this invention. The second portion 20 islarger in dimensions than the first portion 22. The two portions are ofany shape or size suitable to the soft tissue defect, as discussedabove. The first and second portions are arranged in substantially twolayers and are joined along the interface 24 by any known means, asdiscussed above.

FIG. 3 illustrates another embodiment of this invention. In thisembodiment, the second portion 30 is larger than the first portion 32 inseveral dimensions, and the portions are arranged such that theperimeter of the second portion extends beyond the perimeter of thefirst portion in substantially all directions. The first and secondportions are illustrated as rectangular but may be of any suitable sizeand shape, and the two portions may optionally be joined together by anyknown means. This embodiment advantageously provides a large surface forfascial replacement.

FIG. 4 illustrates another embodiment of this invention. In thisembodiment, the second portion 40 is larger than the first portion 42 insubstantially only one dimension, and the portions are arranged suchthat the perimeter of the second portion extends beyond the perimeter ofthe first portion in fewer than all directions. The two portionsoptionally may be joined together by any known means, as discussedabove.

FIG. 5 illustrates a view in cross-section of a further embodiment ofthe present invention. The first portion 50 and the second portion 52are arranged in layers, but they are not joined together, and a space 54is present between the first and second portions.

FIG. 6 illustrates a view in cross-section of another embodiment of thepresent invention. The first portion 60 and the second portion 62 arejoined partially along the interface 64 by any known method, asdiscussed above.

FIG. 7 illustrates a top view of a further embodiment of the presentinvention. In this embodiment the first portion 70 and the secondportion 72 are arranged to form substantially a single layer, whereinthe second portion substantially surrounds the first portion. Theportions may be of any size or shape suitable to the soft tissue defect.The portions optionally may be joined along the interface 74 by anyknown means of joining, as discussed above.

FIG. 8 illustrates a side view in cross-section of the embodiment shownin FIG. 7. The first and second portions 70 and 72 are joined along theinterface 74.

FIG. 9 illustrates a side view in cross-section of another embodiment ofthe present invention. The first and second portions are integrallyformed as a single layer 90. Thus, the single layer comprises twodifferent materials, each providing the different features discussedabove.

In the figures which are referenced in the following discussion,anatomical elements appearing in more than one figure are indicated bythe same reference numerals in each figure.

As mentioned above, the prosthesis of the present invention can beutilized in the repair of hernias, and, in particular, in the repair ofincisional hernias.

FIG. 10 illustrates the normal anatomy of the abdominal wall. Theabdominal wall consists of skin 100, subcutaneous fat 102, fascia 104,muscle 106, and a thin lining 108 called the peritoneum. Of theselayers, it is the firm layer of fascia 104, a thin fibrous tissue, thatprovides strength to the abdominal wall, maintains the integrity of theabdominal wall and is able to hold sutures for repair of hernias.

FIG. 11 illustrates the alteration in the abdominal wall that occurswhen a hernia is present. There is a defect present in the fascial layer104 that allows for protrusion or entrapment of abdominal content. Inthis case, the fascia is separated, and the peritoneum 108 protrudesthrough the separation, forming a "hernia sac."

In the repair of hernias, the first and second portions advantageouslyare arranged such that the first material covers the contents of theabdominal cavity and serves as a replacement for the peritoneal surface,and the second material allows for further incorporation into the host'stissue and/or increases the structural integrity of the prosthesis tolimit the effects of bulging, curling and wrinkling. The prosthesis isimplanted into the patient using standard surgical techniques such thatsubstantially all of the defect in the patient's fascia is closed.

FIG. 12 illustrates one embodiment of this invention in the repair of ahernia. In this embodiment, a prosthesis of this invention is surgicallyimplanted such that the first portion 120 covers the fascial defect 122and the second portion 124 is located above the first portion, and isexposed substantially only to the host's subcutaneous fat layer 102. Thetwo portions are fastened to the muscle fascia 104 by means of sutures126 and 128, such that substantially all of the defect is closed.

In this arrangement, the first portion 120 covers substantially all ofthe opening and prevents the underlying viscera from being incorporatedinto the second portion 124. The second portion 124 provides additionalstructural integrity to the prosthesis and/or facilitates incorporationof the prosthesis into the host tissue.

FIG. 13 illustrates another embodiment of the present invention in therepair of a hernia. In this embodiment, a prosthesis comprising firstand second portions 130 and 132, respectively, that are partially joinedis surgically implanted using suture fixation to two different abdominallayers, namely, the fascia 104 and the peritoneum 108. In thisembodiment, the second portion 132 is sutured via sutures 134 and 135 tothe fascia 104 and the first portion 130 is sutured via sutures 136 and137 to the peritoneum 108. In this embodiment, a portion of the secondportion 132 is exposed to muscle 106. If the second portion comprises amaterial that will substantially incorporate into the host tissue, suchincorporation will be into the strong muscle layer 106, and will lendstrong, durable fixation of the prosthesis into the host tissue. Whilethe peritoneum 108 is not strong enough to hold a prosthesis in place onits own, the combination of suturing the second portion 132 to thefascia 104 and the first portion 130 to the peritoneum 108 providesextra strength and a safeguard in case either the peritoneum or thefascia loses its ability to hold sutures.

When attaching one portion to the peritoneum and another to the fascia,it may be preferred that the two portions be at least partially joined.This structure may provide a stronger repair and minimize thepossibility of fluid build-up in the space between the first and secondportions. Further, the portion attached to the peritoneum, if unattachedto the other portion, could migrate if the attachment to the peritoneumwould fail.

However, prostheses in which the first and second portions are notjoined also may be advantageous and clearly such prostheses arecontemplated. In fact, it has been observed that, in one instance in aprosthesis wherein the first portion comprised expanded PTFE and thesecond portion comprised polypropylene mesh and wherein the two portionswere not joined together, the first and second portions adhered to eachother after a few months.

FIG. 14 illustrates another embodiment of this invention, in which aprosthesis of this invention is used to repair a hernia. The prosthesisused is similar to those illustrated in FIGS. 2-4, where the secondportion is larger than the first portion. As shown, the second 140portion extends beyond the fascial defect 141 and is sutured via sutures142 and 144 to the underlying fascia 104 separately from the firstportion 146 and away from the fascial defect. The first portion 146 issutured to the fascia 104 via sutures 148 and 149. Suturing the secondportion 140 away from the fascial defect, i.e., to a stronger part ofthe fascia 104, provides a more durable, more secure implant thansuturing the second portion 140 near the defective fascia.

Using a prosthesis similar to that illustrated in FIG. 3 in thisembodiment may have an additional advantage. Most recurring herniasoccur at the suture line of the original repair. Since the prosthesis ofthis embodiment extends well beyond the fascial defect and is sutured tothe fascia away from the defect to a stronger part of the fascia, thisembodiment may reduce the risk of developing additional hernias lateralto the prosthesis.

FIG. 17 illustrates another embodiment of the present invention in therepair of a hernia. In this embodiment, the first portion 170 is sizedso that it may be implanted to overlap the peritoneum 108 and extendbeyond the fascial defect 171. The first portion may be larger than thesecond portion. As shown, the first portion is attached via sutures 177through the peritoneum 108 to the fascia 104. The sutures may be, forexample absorbable-through-and-through mattress sutures. The secondportion 172 is attached to the fascia 104 via sutures 174.

This embodiment offers several advantages. First, because the firstportion is larger than the fascial defect, and is implanted so that itoverlaps the peritoneum, the first potion can absorb much of the outwardpressure that exists along the herniated region. This relieves pressurefrom the second portion, and lessens the disruption along the interfacebetween the second portion and the fascia.

Attaching the first portion through the peritoneum to the fasciaprovides extra strength when compared to the embodiment where the firstportion is attached to the peritoneum alone. Furthermore, suturing thefirst portion to the peritoneum and fascia away from the defect, i.e.,to a stronger part of the fascia, provides a more durable and moresecure attachment of the prosthetic device. Also, because a portion ofthe second portion 172 is exposed to muscle 106, if the second portioncomprises a material that will substantially incorporate into the hosttissue, such incorporation will be into the strong muscle layer. Thiswill further enhance the strength and fixation of the prosthesis intothe host tissue.

As discussed above, it may be preferred that the two portions be atleast partially joined, for example, with sutures 176. However,prostheses in which the first and second portions are not joined alsomay be advantageous and clearly such prostheses are contemplated.

FIGS. 18 illustrates a top view of the embodiment of FIG. 17. The secondportion is not shown. The dotted line represents the first portion 170which is attached through the peritoneum to the fascia 104 via sutures177, and overlaps the defect 171.

FIG. 19 illustrates a top view of the embodiment of FIG. 17 with boththe first portion 170 and second portion 172 illustrated. The secondportion may be partially joined to the first portion, for example, viasutures 176. The first portion 170, represented by the dotted line, isattached through the peritoneum to the fascia 104 away from the defect171, while the second portion 172, represented by the shaded area, isattached to the fascia closer to the defect.

The prosthesis of the present invention is suited to hernias of anysize. Typically, hernias will range in size from about 3 cm to about 20cm or more at the widest point. The first and second portions are sizedaccording to the size of the hernia, and preferably will be sized to atleast substantially completely cover the soft tissue defect. Each of thefirst and second portions may be sized to extend beyond the defect inone or more directions, and the portions may be of the same or differentdimensions, and may have the same or different areas. Accordingly, eachof the first and second portions may be sized from about 3 cm to about20 cm or more at the widest point.

EXAMPLES

The following examples are illustrative only, and are not to beconstrued as limiting the scope of the invention.

A prosthesis comprising a first portion comprised of expanded PTFE and asecond portion comprised of polypropylene mesh was used in the repair ofincisional hernias in thirteen patients. The patients ranged in age fromthirty-two to seventy-five years. There were five men and eight women.The hernia defects ranged in size from five to twenty centimeters. Fourof the patients were obese.

The patients included:

a thirty-seven-year-old female who developed a hernia in a lower midlineC-section incision;

a seventy-five-year-old-female who developed a hernia following closureof a temporary colostomy site in the right upper quadrant of theabdomen; and

a thirty-eight-year-old female who developed a recurrent hernia in agall bladder incision following a repair with expanded PTFE used alone.

Various techniques were used to anchor the first and second portions ofthe prosthesis in place. In some instances the first and second portionswere sutured in place separately, while in other instances the first andsecond portions were secured together by sutures or hemoclips beforebeing sewn onto the abdominal wall defect. In one patient there wassufficient peritoneal tissue to allow separate peritoneal closure; inall other patients the prosthesis was used to replace both theperitoneal and fascial surfaces.

Routine perioperative care included the administration of broad spectrumantibiotics pre-operatively and for at least forty-eight hourspost-operatively. Closed suction drainage was used for forty-eight hoursand patients were fitted with an abdominal binder to be worn in theinitial post-operative period.

There were no wound infections complicating the immediate post-operativeperiod in any patient, but one patient, a sixty-seven-year-old male,developed a dehiscence of his skin closure which resulted in exposure ofthe prosthesis and allowed a late infection of the wound. Although nopersistent sinus tract or obvious sepsis occurred, the prosthesis waslater removed. No adhesions of the underlying viscera to the prosthesiswere noted at the time of removal.

In one particular case, a prosthesis similar to that illustrated in FIG.5 was surgically implanted to repair a hernia in an obese,sixty-year-old female. This patient developed post-operative painlateral to the anchored prosthesis. A seroma was drained underultrasound guidance and although the seroma did not recur, the patientcontinued to have localized pain and subsequently manifested a hernialateral to the placement of the prosthesis.

The remaining patients in this series have all had unremarkablepost-operative courses and are continuing to be monitored. The shortterm results demonstrate that the composite prosthesis can besuccessfully used in the repair of abdominal wall defects.

To prevent the development of recurring hernias lateral to theprosthesis, the embodiment illustrated in FIG. 3 has been used in therepair of hernias. FIG. 15 is a top view of an abdominal wall 150 with ahernia 152 which was repaired with a prosthesis of this embodiment. (Theskin and subcutaneous fat layers are not shown.) In this repair, theexpanded PTFE portion 154 was sized and shaped to fit the size and shapeof the hernia 152 and the polypropylene portion 156 was larger than theexpanded PTFE portion and extended beyond the expanded PTFE portion inessentially all directions. The polypropylene portion and the expandedPTFE portion were not joined together prior to being implanted in thepatient. The prosthesis was implanted as described above in reference toFIG. 14.

FIG. 16 illustrates a view in cross-section of the abdominal wall repairillustrated in FIG. 15. The polypropylene portion 156 extended beyondthe hernia 152 and was attached via sutures 162 and 164 to the fascia104, separately from the expanded PTFE portion 154 and away from thehernia 152. The expanded PTFE portion 154 was sutured to the fascia 104via sutures 168 and 169. This configuration provided a large surface ofpolypropylene for fascial replacement and attached the polypropyleneportion to a stronger part of the fascia, minimizing the risk ofdeveloping additional hernias lateral to the prosthesis.

The following is a prophetic example. The prosthesis illustrated inFIGS. 17, 18 and 19 is used to perform an abdominal wall repair. Thefirst portion 170 comprises PTFE, and is sized to extend beyond thehernia defect 171. It is attached by absorbable-through-andthrough-mattress sutures through the peritoneum 108 to the fascia 104away from the hernia defect. The second portion 172 comprisespolypropylene, and is attached to the fascia 104 by sutures 174. Thefirst and second portions are joined by a central row of sutures 176.This embodiment allows the first portion to absorb much of the pressurealong the herniated region, thereby lessening pressure and disruptionalong the interface of the fascia and the second portion.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the compositions and processof this invention. Thus, it is intended that the present invention coverthe modifications and variations of this invention provided they comewithin the scope of the appended claims and their equivalents.

What is claimed is:
 1. A process for treating a soft tissue defect of apatient comprising the step of surgically implanting adjacent the softtissue defect a prosthesis comprising:a first portion comprising a firstmaterial which substantially does not incorporate into the host tissue,wherein said fist portion is sized to extend beyond said defect, and asecond portion comprising a second material selected from the group ofmaterials consisting of a material which substantially incorporates intothe host tissue, a material which increases the structural integrity ofthe prosthesis, and a material which does both.
 2. The process of claim1, wherein said second portion substantially completely covers said softtissue defect.
 3. The process of claim 2, wherein said first portion islarger in area than said second portion.
 4. The process of claim 1,wherein said second portion is attached to said first portion.
 5. Theprocess of claim 1, wherein said soft tissue defect is a hernia.
 6. Theprocess of claim 5, wherein said second portion is surgically attachedto the fascia and said first portion is surgically attached to thefascia through the peritoneum.
 7. The process of claim 6, wherein saidfirst portion is attached to the fascia through the peritoneum byabsorbable-through-and-through mattress sutures.
 8. The process of claim5, wherein said hernia is an incisional hernia.
 9. The process of claim5, wherein said hernia is of a size of from about 3 cm to about 20 cm ormore in width.
 10. The process of claim 9, wherein said second portionsubstantially completely covers said soft tissue defect.
 11. The processof claim 10, wherein said first portion is larger in area than saidsecond portion.
 12. The process of claim 9, wherein said first portionis of about the same area as said second portion.